+static int eval_op_sum(uschar **sptr, BOOL decimal, uschar **error)
+{
+uschar *s = *sptr;
+int x = eval_op_mult(&s, decimal, error);
+if (*error == NULL)
+ {
+ while (*s == '+' || *s == '-')
+ {
+ int op = *s++;
+ int y = eval_op_mult(&s, decimal, error);
+ if (*error != NULL) break;
+ if (op == '+') x += y; else x -= y;
+ }
+ }
+*sptr = s;
+return x;
+}
+
+
+static int eval_op_shift(uschar **sptr, BOOL decimal, uschar **error)
+{
+uschar *s = *sptr;
+int x = eval_op_sum(&s, decimal, error);
+if (*error == NULL)
+ {
+ while ((*s == '<' || *s == '>') && s[1] == s[0])
+ {
+ int y;
+ int op = *s++;
+ s++;
+ y = eval_op_sum(&s, decimal, error);
+ if (*error != NULL) break;
+ if (op == '<') x <<= y; else x >>= y;
+ }
+ }
+*sptr = s;
+return x;
+}
+
+
+static int eval_op_and(uschar **sptr, BOOL decimal, uschar **error)
+{
+uschar *s = *sptr;
+int x = eval_op_shift(&s, decimal, error);
+if (*error == NULL)
+ {
+ while (*s == '&')
+ {
+ int y;
+ s++;
+ y = eval_op_shift(&s, decimal, error);
+ if (*error != NULL) break;
+ x &= y;
+ }
+ }
+*sptr = s;
+return x;
+}
+
+
+static int eval_op_xor(uschar **sptr, BOOL decimal, uschar **error)
+{
+uschar *s = *sptr;
+int x = eval_op_and(&s, decimal, error);
+if (*error == NULL)
+ {
+ while (*s == '^')
+ {
+ int y;
+ s++;
+ y = eval_op_and(&s, decimal, error);
+ if (*error != NULL) break;
+ x ^= y;
+ }
+ }
+*sptr = s;
+return x;
+}
+
+
+static int eval_op_or(uschar **sptr, BOOL decimal, uschar **error)
+{
+uschar *s = *sptr;
+int x = eval_op_xor(&s, decimal, error);
+if (*error == NULL)
+ {
+ while (*s == '|')
+ {
+ int y;
+ s++;
+ y = eval_op_xor(&s, decimal, error);
+ if (*error != NULL) break;
+ x |= y;
+ }
+ }
+*sptr = s;
+return x;
+}
+